Acquired immune deficiency syndrome, or AIDS, is an infectious disease which weakens the immune system to the point that the body cannot defend itself against diseases and infections that it can normally resist. In some cases, it is these Opportunistic disease, as they are called, that cause the fatalities. AIDS is caused by an infection brought on by the human immune deficiency virus (HIV) that scientists have identified as a retrovirus.
In the immune system of healthy people, white blood cells and antibodies attack and destroy germs and other foreign organism as they enter the body. The T-cell lymphocyte, also known as T-helper, T-4 or CD4, is one of the white blood cells that assist in destroying foreign proteins, an immune system response that prevents people from getting sick. Unfortunately, these are the cells HIV targets.
HIV cannot live independently. It attaches and enters the T-helper lymphocytes so that it will be able to multiply. HIV incorporates its HIV genes into the host cells and then replicates within the T-helper lymphocytes. When the newly-formed viruses break out of their cells, they continue the cycle by infecting more T-helper lymphocytes.
At some point, the body's own defenses contribute to the problem, as the immune system tries to overcome the infection by producing additional helper cells, providing yet more hosts for the virus. Eventually the system can no longer produce enough white blood cells to ward off other infections.
When the disease progresses from HIV infection to full-blown AIDS, it is because the number of T-cells has dropped to dangerous levels. AIDS is heralded by a total lymphocyte count of less than 500/mm3 and a dangerously low T-cell count of below 200. With the immune system so depleted, the body becomes highly vulnerable to opportunistic diseases. As the term suggests, these are infections and other diseases that seize the opportunity presented by a weakened defense system. They commonly include herpes simplex infection and other herpes conditions such as shingles and the oral yeast infection, thrush; Kaposi's sarcoma, characterized by the dark lesions; CKV retinitis, a herpes virus that can bring blindness; meningitis, an infection of the spinal cord and brain; cervical cancer; and a formerly rare type of pneumonia.
The Department of Health & Human Services (“DHHS”) has issued guidelines recommending certain antiretroviral agents for treatment of established HIV infection. The DHHS panel recommended that all patients with less than 500 CD4 T cells/mm, and a viral load greater than 10,000 (bDNA) or 20,000 (RT-PCR) copies of HIV RNA/ml, of plasma should be offered antiviral therapy. The use of various combinations of antiretroviral agents represents the current state of the art and significant benefits have been observed in many cases although the long term results remain to be established. The patients presently must adhere to complex dosage regimens and tolerate significant drug side effects and adverse reactions.